Method for manufacturing pyrometric cones



June 5, 1945. G. A. BoLE ETAL Y 2,377,566

METHOD FOR MANUFACTURING PYROMETRIC CONBS 4 l Filed Aug. 18,' 1943 i 2 ShGeLS-Sllef 1 44 i gwuwvbom GEORGE. A. Bon-E. MYRIL C4. SHAW l HARRY E. CoVAN June 5, 1945. G, A BOLE ETAL 2,377,666

METHOD FOR MANUFACTURING PYROMETRIC CONS Filed Aug. V18,` 1943 l 2 Sheets-Sheet 2 I GEORGE. A-B0LE, 329 /6 46 .mri/ 37 MYILIL. C. SHAW HARRY E- CoVAN l liable means for ascertainingthe heat trea `sonnel'engaged in making the cones.

, A common practice has consisted Patented June 6 e A "METHOD Fo 2,377,666 e e l RMANUFACTURING e PYROMETRIC coNEs f `George A, 6 Bole, Myril Co Van, Columbus, Edward `(Zlrton Jr.

Columbus, Ohio, `a testamentary trust Application AugustflS 2 Claims. rl'his `irn/ention relatesu an improved `method forV molding ceramic bodies, and although4 itis not so limited, theinvention has particular applicationto the production of pyrom'etric cones.

vSuch cones comprise' three-sided pyramidal bodies ofceramic composition. their practical employment, the sameyconesare used for determining ring temperatures in kilns in which ceramic products of various types are subjected to firing or maturing temperatures. When "so used, the larger or base ends of the cones areembedded in plaquesl with the cones arranged in upright positions and: slightly inclined `in a forward ydirection with respect tov ,the vertical. Theseplaque-carried cones -arefplaced inthe liring zones of kilns and when the latter are fired and desired maturing heat treatment `therein attained,f such `heat-treating conditions may be readily ascertained by` observing the physical condition of the cones, the latteribeing so formed and positioned `that at predeterminedheat treatl ment, the glassy phaseof the composition from which they are formed softens, allowing the'cones tobend forwardly and downwardly from their normallystraight and upright positonsfrsuch` bending or deflection of the cones serving as a re-` l tment producing maturity of the-ceramic ware. `j y c It is importantl in their manufacture that such `cones shall possess uniform `and standardized properties, so that duplicate lcones willfuniformly ,respond toi predetermined kiln temperatures `of ijs` attributable, at least in part, to the `use of molding apparatus and procedures requiringthe exerciseof skill andl care on the part of the per- Also, the workability ofl theindividual hatches,l the temperature and humidity lof the workroom and many other conditionsV were factors inthe production of satisfactory* cones under prior" sys-'- tems,` `these variables having :been eliminated py the present invention.

e in ,inserting clayin a moldable, moisture-containing" plastic state in the cavities of metallic molds,`surplus y materialfbeing then removed inl order to` leave l, within the cavities soft clay bodies having, in generaLlthedesired shape of commercial cones. Practically, however considerable variation` in proportion has been present, such variations havinzlbeen due to` different causes, such as the 6 C. Shaw, and Harry E.

Ohio, assignorsto The 6 6 Ceramic lloundatron,` l

,1943,` Serial Ne.499`,"1`48" 'p (onza-'156) v e l ,l l, t e

failure of the operator'tol fill completelythe cavities with the moldable material,` particularly `atthe end portions of` the cavities, with theresult that inequalities the length :or height ofy 5 'the cones has been a matter of commonoccurrence.r `Also in suchprior practice, immediately following themolding ofthe; undried cones, the latter by a manually executedoperation, and ,while still in af moist plastic state, were removed 10 from themoldjcavities and deposited Von drying pallets, Such` handling of theplasticcones re'- sult,"quite `frequently, 'inwsetting up therein intermal `stresses andistrainswhich, upon subsequent` drying of thecones, caused their warpage or deilectionnrendering the :cones imperfect and unsuitable for commercial use. f

",Itfis, therefore, an object ofthe pres 0 facteriaed by `their structural uniformity, f'their bending response to predetermined kiln tempera- `(tures "ofjllmited` range, and their standardized weight; composition land dimensions.

" L Another object is `to provide `an improved an improved` method Vfor making such cones wherein: the "mold iscomposed of l a moistureabsorbing'material, such as plaster, andin which `mold the cones are-retained `until the material comprising the same 6 is sufficiently dried so that 6 internal stresses "and strains, `incident dling, will not occur therein.` l

l Still,` a further objecty ofthe invention is to systematize and render more efiicient and less "costly the manufacture of `pyrornetric cones with respect topriorprocedures;` l

o l Forge; further understanding of `the invention,

`reference isto be had to the following description and-the accompanying drawings, wherein:

` ".Fig. 1` isfadiagrammaticview,` partly in side elevation and vertical section,` ofV extrusion ap- "paratus for producing i pugged` and de-airedl c lay columns,A andr for cutting such columns into `blanks 4suitable for insertion in molds;

j l Fig. 2 is anuendz elevationalview of the head of theextrusion apparatus; 6 e

QfFiglS is a front elevational view ofthe s operated column-putting mechanism; i a transverse verticalsectional view `taken `through `tl`iecor1veyor belt and vits associted switch'mechanism; e

i. Fig; 5215 aiperspectiveyiew of oneofthe molds;

die

olenoid e entinvention to provide an improvedmethod formoldingl `pyrometric cones, wherein the latter are charto hanl Fig. 6 is a vertical transverse section-al view taken through the mold;

Fig. 7 is a fragmentary longitudinal sectional view taken through the mold on the plane indicated bythe line 'l--l of Fig. 6;

Fig. Sis `a perspective viewof a--pyrometric cone formed in accordance with the present invention; f

Fig. 9 is a similar view of one of the soft clay blanks `adapted for insertion in the mold cavities;

Fig. 10 is a perspective view disclosing the mold press, with the head of the press disposed in its elevated position; Y, r i t Fig. 11 is a fragmentary vertical longitudinal sectional View taken through 'thepress and disclosing the head thereof in its lowered position;

Fig. 12 is a perspective` view disclosing the means for stamping indicia on the cones and the" tecting fingers of the press mechanism.

In accordance with the present' invention, 'the pyrometric cones areproduced by'pugging a mass of moistureLcontaining plastic cone mixa'nd, following such pugg'ing, andvvvhilethe'fbody is in a granulated or discretestatefthe"same is passed through a chamber inwhicha fpa'rtial vacuurnis continuously maintained, wherebyfto remove from the batch occludedv air.k From 'this defairing chamber, thev clay mixture is forcedthrou'gh an extrusion die by a continuing operation' to form .a dense,f homogeneouscolumn or Aribbon.A This column is delivered 'to a .traveling conveyor through two equilateral triangularforices in a metal die, and,'jpreferably,by automatic'fmeans,

the column is severed transversely at Spacedlon- .,gitudinal intervals to provide `on the ,belt coneforming blanks 0f desiredjlengthn These blanks areV removed fromV theV conveyor..belt and, by a manual operation, are inserted` into the coneshaping 'cavities Of plastermolds, the Jmaterial in each blank being present V`in excess'arnounts,

above; that actually neededtol completely fill the mold cavitiesin which the sameareinselted.

The molds are `then transferred to a pressing machine having armovableheadLand ,throughv the `operation of this head,. thev clay material is forced rmly into the mold cavities, completely andr uniformly llingthe latter.4 .v Following the pressing operation, Ythe mold is brought into engagement with wire cutters, which remove the surplus clay material from. ytheytop, `and sides of the mold, leaving within the `caivities the, shaped and precise amount of material necessary to form the commercial cones. The molds are then inverted and placed-face down onv plaster slabs or pallets so that Vthe exposed upper surfaces of the cones contained in the mold `cavities will ,bar against a moisture-absorbingl material. Y, The cones are so retained under room; temperatures until the same have partially. dried and shrunk, attaining a permanent form, such `drying being effected as a result of the absorption of moisture from the cones bythe plasterwalls ofthe molds and the associated slabs or pallets. During these operations, except .for the placing of ythe'jc'oneforming blanks in the moldcavities, thefco'nes arel not touchedv byhandbut, on the contrary, `are retained ina` supporte'd'sta'te' in th'molds cones may then be accelerated by positioning the l same in an artificially heated drier.

vApparatus suitable for accomplishing these operations has been diagrammatically illustrated in the accompanying drawings, although it should be understood that other suitable apparatus may be employed.y In Fig. 1` of the drawings, there has been disclosed a, clay extrustion machine comprising a bed I, having mounted thereon a clair pugging sectiony 2 having a hopper or magazine 3 in which batches of moist clay are introduced from time tov time during the operation of the machine. The pugging section includes the `usual clay mixing and advancing,augersfoperated by a motor driven shaft'l', the mixed or pug'ged clay being advanced vfrom thesection 2 vthrough a granulating ordisintegrating section 5 and thence into a de-airing section 6. A p'artialyacuum is maintained on the clay mixture-within said` deairing section in order to remove from theljclay as much of the free and occluded air asis practicable, whereby to render the clay mixture dense and homogeneous throughout itsinass The clay is then advanced by'a suitable auger through an extrusion section 1, the latter having a die Sprovided at its discharge end. Ihisfdie is provided with one or more extrusion openings which are approximately triangular Ain cross section, the clay column or ribbon extruded from `the die, therefore, havingy approximately the` Across `sectional conguration of a pyrometriccone.

The clay column orribbon is deliveredbyv the y extrusion machine tothe upper surfacelof ,a mov'.

able conveyor belts and as ythe material'travels along this belt, the same is Cut transversely to produce cone-forming blanks of suitablelength for insertion into the cavitiesnof. a mold. In a desirable form of the apparatus,` the cutting ofthe clay column or ribbon is accomplished by.- means of a wire cutterhlll. The latter hasits endsA tensionably connected with a reciprocating armature frame l, the upper and lowerends of the frame being positioned within the coils of. solenoids l2. These coils are alternately energized andvdeen-` ergized by being electrically connected withV movable switch arms !3 arranged contiguous tothe longitudinal edges of the belt,` 9.` These belts carry spaced Aelectrical contacts I4, which are in circuit with the solenoid coils. `When aswitch arm engages one of these contacts, the solenoid coil joined with the switch arm is energized, ,at tracting the armature and moving theqwire cuttery across the face vof the extrusionk diei, rthereby severing the clay column transversely as Iitisbeing extruded from the head. j M Y This cutting mechanism `has. `peen^morejully disclosed in our accompanyingjapplication, entitled Extruding and cutting apparatus, executed lof, even date herewith. yWhile lother equivalent which have been thoroughly pugged and tdefaired.

The cone-forming blanks areremovedffrom rthe belt llV and manually inserted Yinto.thlfe` cavities of a mold of 'thetype shown at..|.5. This mold in a practical embodiment is Vof block-like form and is composed of a -water-absorbingma cutter 35.

- faszfacec 1' terial, such as calciumsulphate "compounds, par- `.ticularly plaster ofrParis;` `liachrmoldwisprovfided with a` pluralityof cone-forming cavities :15, the

i same beingopen at their tops and ends and hav- .ing v-shaped sidewalls |11, each cavity having. abottom edge I8 inclined-at anacute angle with respect to the horizontal, so thatthe cavity at `one side or end of the mold is ycomparatively deep and at the other side or end relatively With the blanks positionedin the various cavitiesof the mold, Athe latteris transferredl to `a pressing machine `disclosed at I9; oWhile this machine `has beendisclosedinidetail, in ourapplication entitled Machine for molding pyrometric cones" and executed of even date herewith, the same embodies generally a bed 20 on j which is arranged a sliding bed plate 2|: fThe `bed plate carries at oneenda mold-positioning `block 22, the saidblo'ck having an upright shoulf dered wall 23 and against this wall one -of the side edges ofa mold l `is positioned. `Carried by the `block 22 is a pivoted arm 24, and upon theouter end of this arm there is mounted a `mold-pressing head 2,5.

Arranged on the upper surface of the bed support of a finger bar 21.. This bar carries a plurality of spaced, forwardly projecting, metallic fingers 23 of triangular configuration which project `over and protect the triangular upper surfaces 29 of the mold' l5, which surfaces are disposed between the mold cavities lli.` In the surfaces 29, the mold is provided with grooves 30, which receive supporting and reenforcing rods 3| carried by the bar 21 and arranged immediately beneath the fingers 28.

`The bed is provided centrally with a groove 32 whichreceives a rib 33 depending, asa guide element, from the bed plate 2|. Also, the sides of the bed 2l) are provided with brackets 34, which effect the support of a tensionable wire In the use of this pressing having the clay cone-forming blanksinserted in its cavities, is positioned against the wall 23 of the block 22,9and with the shallower ends of the cavities disposed toward the finger bar 21. This bar is then moved on its guides 26 so that the fingers 28 are arranged over and in protecting relationship with the surfaces 29 of the mold, the reenforcing rods `3| of said fingers occupying th grooves 3D. With the molds so positioned, the pressing head is forced downwardly, pressing the clay blanks firmly into the mold cavities and completely and compactly filling the latter.

The bed plate 2|A is then moved rearwardly, saus-- ing the cutter wire to wipingly engage the upper surfaces of the ngers 28, producing on the plastic clay bodies, arranged within the mold cavities, a smooth, clean upper surface. The excess material released by this cutting operation adheres to the contacting surfaces` of the head 25 and, after the latter has been raised, may be i removed therefrom.` I

The mold is then removed from the pressing machine and is placed on a table 36 having a longitudinal guideway 31, the` width of `which guideway approximates that of the mold. At one end of this guideway, there is arranged a` counterbalanced lever 38 which carries at its outer end a cross arm 40. This arm carries conemarking dies disclosed at 4I, B2 and 4,3, the latter being so shaped that when the lever`38 is swung downwardly, the dies will impress in the machine, a mold,

` Vfying `number `or 'other symbol disclosing, in a` larger or base .ends ofthe 'cones informative indicia, such `as a depth mark 44=which`indicates on the cone 45 the depth at whichthe icone :should ;be embedded in a supporting plaque.

Also, the dies may stamp on` the cone an identimanner known to the trade, the temperature characteristicsof the particular` cone `bearing the symbol, and the third of` these` dies may stamp on the cone the 4irianufacturers.trade-mark;

Following this stamping operation, the molds are advancedlongitudinally;of the guideway` 31 and are"broughtinto engagement ywith a pair 1of cutter wires 46. .The movement of the mold past these" cutterwires severs `from ythe cones any surplus material whichwmayproject from plate 2| are guides 26, which effect the slidable theopen endsof thecavities, producing smooth base and apex` surfaces and causing the cones to possess a uniform length orheightdimension. l Upon the removal of the mold or molds from the table 3B, the same are invertedl and placed face-down upon a plaster slab `orlpallet`41, so

that the exposed upper surfaces of the'cones t will be brought into engagement with a moisture- Vabsorbing body corresponding in this `respect to the `material from which the molds `areformed.

Under such conditions, the cones are retained within the molds and in contactwith the slabs or pallets fora period of from 2 to 3ho'urs. At the conclusion of this period, suicient moisture will have been absorbed from the cones by the molds and theslabs orypallets and, also, as a result of air dryingto` cause the cones to set and harden and assume permanent form. l

:It Will be noted that during the pressing, cutting and drying operations, the cones are continuouslyretained within the molds and` are not subjectedto manual handling, as heretofore. As previously stated, when cones in the plastic state are removed from the molds, such an operation isI quite likely to set up internal stresses which result in the final Aformation of imperfect products.` This condition is expressly overcome by the procedure above set forth.

Following the initial setting and drying of the cones, and upon `their attaining a desire-d degree of permanency in their structure, the molds are lifted from the slabs or pallets 41. Due to drying shrinkages, the cones freely drop out of the cavities IB and may remain on the upper surfaces of the slabs or pallets or other support. If desired, the same may then be inserted in an arti-I iiciallyl heated drier maintained at a temperature approximately 150 F. for a period of 12 hours, thus completingthe manufacturing operations. In practice, these cones are then packed in cartons or boxes for shipment to points of use.

In View of theforegoing, it will be seen. that the present invention provides an improved method and apparatus adapted for the systematic, rapid and uniform production of pyrometric cones. Cones so produced will respond uniformly in a definite and predetermined manner to different ring temperatures usedin the kiln burning of ceramic products. are uniform in weight and dimensional factors and'constitute reliable temperature indicators for the use set forth. The invention further has the advantage of permitting such cones to be produced rapidly, at low cost and without employing necessarily highlyA skilled operators.

While we have expressed our invention in terms V of its use inthe manufacture of pyrometric cones, i nevertheless, it will be understood that our invention is applicable `to the manufacture of many The cones of any given set` other molded ceramic articles intended for en- .the blanks While in said mold to pressure sufiicient to cause the material comprising said Iblanks to completely ll the full volume of said cavities, While pressure is maintained on the blanks effecting relative movement between the mold and a cutting instrumentality in order to sever and remove surplus material disposed above the mold cavities, moving the sides ofthe mold past second cutting instrumentalities to remove surplus material projecting from the ends of the mold cavities, and without removing the coneforming material from the mold cavities causing said material to dry. l

2. The method of producing pyrometric cones which comprises severing a column of extruded cone-forming material to form molding blanks of appropriate length and body, placing said blanks in the cavities of the mold wherein each cavity possesses a lesser volumetric capacity than the volume of the blank inserted therein, subjecting the blanks while in the mold to pressure suiiicient to cause the moldable material to fill completely the full volume of each cavity, while pressure is maintained on the blank effecting relative movement between the mold and a cutting instrumentality in order to sever and remove surplus material disposed above the mold cavities, moving the sides of the mold past second cutting instrumentalities to remove surplus material projecting from the ends of the mold cavities, inverting the molds and placing the same face down on a slab having water-absorbing properties, retaining the molded cones in said mold and in contact with said slab to cause the same to harden as a result of moisture absorption by the mold and slab and the drying eiects of atmospheric air at normal temperatures, and thereafter removing the cones from the mold cavities and subjecting the same to higher drying temperatures.

GEORGE A. BOLE. MYRIL C. SHAW. v HARRY E. CO VAN. 

